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[proxmark3-svn] / client / tinycbor / utf8_p.h
1 /****************************************************************************
2 **
3 ** Copyright (C) 2017 Intel Corporation
4 **
5 ** Permission is hereby granted, free of charge, to any person obtaining a copy
6 ** of this software and associated documentation files (the "Software"), to deal
7 ** in the Software without restriction, including without limitation the rights
8 ** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 ** copies of the Software, and to permit persons to whom the Software is
10 ** furnished to do so, subject to the following conditions:
11 **
12 ** The above copyright notice and this permission notice shall be included in
13 ** all copies or substantial portions of the Software.
14 **
15 ** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 ** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 ** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 ** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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20 ** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21 ** THE SOFTWARE.
22 **
23 ****************************************************************************/
24
25 #ifndef CBOR_UTF8_H
26 #define CBOR_UTF8_H
27
28 #include "compilersupport_p.h"
29
30 #include <stdint.h>
31
32 static inline uint32_t get_utf8(const uint8_t **buffer, const uint8_t *end)
33 {
34 int charsNeeded;
35 uint32_t uc, min_uc;
36 uint8_t b;
37 ptrdiff_t n = end - *buffer;
38 if (n == 0)
39 return ~0U;
40
41 uc = *(*buffer)++;
42 if (uc < 0x80) {
43 /* single-byte UTF-8 */
44 return uc;
45 }
46
47 /* multi-byte UTF-8, decode it */
48 if (unlikely(uc <= 0xC1))
49 return ~0U;
50 if (uc < 0xE0) {
51 /* two-byte UTF-8 */
52 charsNeeded = 2;
53 min_uc = 0x80;
54 uc &= 0x1f;
55 } else if (uc < 0xF0) {
56 /* three-byte UTF-8 */
57 charsNeeded = 3;
58 min_uc = 0x800;
59 uc &= 0x0f;
60 } else if (uc < 0xF5) {
61 /* four-byte UTF-8 */
62 charsNeeded = 4;
63 min_uc = 0x10000;
64 uc &= 0x07;
65 } else {
66 return ~0U;
67 }
68
69 if (n < charsNeeded)
70 return ~0U;
71
72 /* first continuation character */
73 b = *(*buffer)++;
74 if ((b & 0xc0) != 0x80)
75 return ~0U;
76 uc <<= 6;
77 uc |= b & 0x3f;
78
79 if (charsNeeded > 2) {
80 /* second continuation character */
81 b = *(*buffer)++;
82 if ((b & 0xc0) != 0x80)
83 return ~0U;
84 uc <<= 6;
85 uc |= b & 0x3f;
86
87 if (charsNeeded > 3) {
88 /* third continuation character */
89 b = *(*buffer)++;
90 if ((b & 0xc0) != 0x80)
91 return ~0U;
92 uc <<= 6;
93 uc |= b & 0x3f;
94 }
95 }
96
97 /* overlong sequence? surrogate pair? out or range? */
98 if (uc < min_uc || uc - 0xd800U < 2048U || uc > 0x10ffff)
99 return ~0U;
100
101 return uc;
102 }
103
104 #endif /* CBOR_UTF8_H */
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